Two police officers have been killed and 18 people wounded in a car bomb attack in the city of Gaziantep, in south-east Turkey.

Turkish media reported on Sunday that police had identified at least one of the attackers as Ismail Günes, who is said to have been an Isis member. His father, Süleyman Günes, has been detained for questioning.

The daily Hürriyet newspaper reported that the attackers first opened fire on the police from a car before a second vehicle carrying explosives was detonated in front of the police headquarters building. One of the cars is said to have escaped, and security forces have begun a search for the vehicle involved in the attack.

Mehmet Erdoğan, Gaziantep MP for the ruling Justice and Development, or AK, party, said earlier that the car bomb could have been in retaliation for a police crackdown on Isis cells and the outlawed Kurdistan Workers’ party (PKK) in Gaziantep. Both groups have recently carried out suicide bomb attacks in Turkey.

Gaziantep, a city of about 1.5 million people close to the Syrian border, is also home to a large number of Syrian refugees who have fled the violence in their own country. The European council president, Donald Tusk, the European commission vice-president, Frans Timmermans, and the German chancellor, Angela Merkel, were in the city last week to inaugurate the EU’s new aid programme for Syrians living in Turkey.

The police station that was the scene of this morning’s bombing is near to several government office buildings, including those of the governor and the mayor. Sunday’s planned May Day demonstrations in Gaziantep were cancelled due to the potential security threat. CNNTurk reported that May Day events were also cancelled in the cities of Adana and Sanliurfa after intelligence on possible suicide bomb attacks.

According to the state-run Anadolu Agency, police carried out anti-terrorism raids overnight in the Turkish capital, Ankara. Four suspected Isis militants who had allegedly planned to stage attacks in the city on May Day were detained.

The Gaziantep attack came just four days after a female suicide bomber injured several people outside the grand mosque in Bursa, Turkey’s fourth-largest city.